Carrierless chip package for integrated circuit devices, and methods of making same

ABSTRACT

Disclosed is a carrierless chip package for integrated circuit devices, and various methods of make same. In one illustrative embodiment, the device includes an integrated circuit chip comprising an exposed backside surface defining a plane, a plurality of wire bonds that are conductively coupled to the integrated circuit chip, each of the plurality of wire bonds being conductively coupled to a conductive exposed portion, a portion of the conductive exposed portion being positioned in the plane defined by the backside surface, and an encapsulant material positioned adjacent the integrated circuit chip and the plurality of wire bonds.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to the field of packagingintegrated circuit devices, and, more particularly, to a carrierlesschip package for integrated circuit devices, and various methods of makesame.

2. Description of the Related Art

Microelectronic devices generally have a die (i.e., a chip) thatincludes integrated circuitry having a high density of very smallcomponents. In a typical process, a large number of die are manufacturedon a single wafer using many different processes that may be repeated atvarious stages (e.g., implanting, doping, photolithography, chemicalvapor deposition, plasma vapor deposition, plating, planarizing,etching, etc.). The die typically include an array of very small bondpads electrically coupled to the integrated circuitry. The bond pads arethe external electrical contacts on the die through which the supplyvoltage, signals, etc. are transmitted to and from the integratedcircuitry. The die are then separated from one another (i.e.,singulated) by backgrinding and cutting the wafer. After the wafer hasbeen singulated, the individual die are typically “packaged” to couplethe bond pads to a larger array of electrical terminals that can be moreeasily coupled to the various power supply lines, signal lines andground lines.

Electronic products require packaged microelectronic devices to have anextremely high density of components in a very limited space. Forexample, the space available for memory devices, processors, displaysand other microelectronic components is quite limited in cell phones,PDAs, portable computers and many other products. As such, there is astrong drive to reduce the height of a packaged microelectronic deviceand the surface area or “footprint” of a microelectronic device on aprinted circuit board. Reducing the size of a microelectronic device isdifficult because high performance microelectronic devices generallyhave more bond pads, which result in larger ball/grid arrays and thuslarger footprints.

FIGS. 1A-1B are, respectively, a cross-sectional and top view of anillustrative packaged integrated circuit (IC) device 10. The packaged ICdevice 10 is comprised of an integrated circuit chip 12 that is affixedto a carrier 14 by an adhesive material 18. The chip 12 and carrier 14comprise a plurality of bond pads 20 and 22, respectively. A pluralityof wire bonds 24 conductively couple the bond pads 20 on the chip 12with the bond pads 22 on the carrier 14. Also depicted in FIG. 1A is aconductive structure 28, such as a printed circuit board, a motherboard,a memory module, or the like. The conductive structure 28 typicallycomprises a plurality of insulated traces (not shown) and a plurality ofbond pads 30. In one illustrative embodiment, the chip 12 isconductively coupled to the conductive structure 28 by a plurality ofsolder balls 30. The chip 12 is encapsulated with a molding or epoxycompound 16.

FIG. 1B is a top view of the device 10 with the epoxy compound 16removed. As shown therein, the bond pads 22 on the carrier 14 occupy alot of space. The presence of the bond pads 22 can, in some cases, causethe carrier 14 to delaminate. Such delamination can cause the chip 12 tofail or at least not perform up to its full capabilities. Moreover, thepackaged IC device 10 can be relatively large due to its basicconfiguration, the components involved, and the manner in which it isfabricated. For example, the distance 11 between the edge of the chip 12and the edge of the epoxy compound 16 may range from approximately0.5-1.0 mm. The carrier 14 may have a thickness that varies fromapproximately 125-450 μm, depending on the application and thecomposition of the carrier 14. Similarly, the thickness of the epoxycompound 16 may also vary, e.g., from approximately 0.5-1.2 mm. Thus,the overall height 13 of the carrier 14 and epoxy compound 16 may rangefrom approximately 0.40-1.65 mm.

The present invention is directed to a device and various methods thatmay solve, or at least reduce, some or all of the aforementionedproblems.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an exhaustive overview of the invention. It is notintended to identify key or critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome concepts in a simplified form as a prelude to the more detaileddescription that is discussed later.

The present invention is generally directed to a carrierless chippackage for integrated circuit devices, and various methods of makesame. In one illustrative embodiment, the device comprises an integratedcircuit chip comprising an exposed backside surface defining a plane, aplurality of wire bonds that are conductively coupled to the integratedcircuit chip, each of the plurality of wire bonds being conductivelycoupled to a conductive exposed portion, a portion of the conductiveexposed portion being positioned in the plane defined by the backsidesurface, and an encapsulant material positioned adjacent the integratedcircuit chip and the plurality of wire bonds.

In another illustrative embodiment, the device comprises an integratedcircuit chip comprising an exposed backside surface defining a plane, aplurality of wire bonds that are conductively coupled to the integratedcircuit chip, each of the plurality of wire bonds being conductivelycoupled to a conductive exposed portion, a portion of the conductiveexposed portion being positioned in the plane defined by the backsidesurface, and an encapsulant material positioned adjacent the integratedcircuit chip and the plurality of wire bonds, the encapsulant materialcomprising a bottom surface that is positioned substantially in theplane, wherein a distance from a side of the integrated circuit chip toa side of the encapsulant material ranges from approximately 0.1-0.4 mm.

In yet another illustrative embodiment, the device comprises anintegrated circuit chip comprising an exposed backside surface defininga plane and a plurality of wire bonds that are conductively coupled tothe integrated circuit chip, each of the plurality of wire bonds beingconductively coupled to a conductive exposed portion, a portion of theconductive exposed portion being positioned in the plane defined by thebackside surface, wherein the exposed conductive portions lying in theplane have a substantially rounded configuration. The device furthercomprises an encapsulant material positioned adjacent the integratedcircuit chip and the plurality of wire bonds and a conductive structurethat is conductively coupled to the exposed conductive portions.

In one illustrative embodiment, the method comprises positioning anintegrated circuit chip adjacent a sacrificial structure comprising aconductive portion, the integrated circuit chip comprising a backsidesurface, attaching a plurality of wire bonds to the integrated circuitchip, attaching the plurality of wire bonds to the conductive portion ofthe sacrificial structure to thereby define a conductive portion coupledto each of the wire bonds, forming an encapsulant material adjacent theintegrated circuit chip, the wire bonds and the sacrificial structure,and removing the sacrificial structure to thereby expose the backsidesurface of the integrated circuit chip and at least a portion of theconductive portion that is conductively coupled to each of the pluralityof wire bonds.

In another illustrative embodiment, the method comprises positioning anintegrated circuit chip adjacent a sacrificial structure comprising aconductive layer, the integrated circuit chip comprising a backsidesurface, attaching a plurality of wire bonds to the integrated circuitchip and to the conductive layer of the sacrificial structure to therebydefine a conductive portion coupled to each of the wire bonds, formingan encapsulant material adjacent the integrated circuit chip, the wirebonds and the conductive layer of the sacrificial structure, andperforming a planarization process to remove the sacrificial structureto thereby expose the backside surface of the integrated circuit chipand at least a portion of the conductive portion conductively coupled toeach of the plurality of wire bonds.

In yet another illustrative embodiment, the method comprises positioningan integrated circuit chip adjacent a sacrificial structure comprising aplurality of spaced-apart conductive structures, the integrated circuitchip comprising a backside surface, attaching each of a plurality ofwire bonds to the integrated circuit chip and to one of the spaced-apartconductive structures of the sacrificial structure to thereby define aconductive portion coupled to each of the wire bonds, forming anencapsulant material adjacent the integrated circuit chip, the wirebonds and the sacrificial structure, and performing a planarizationprocess to remove the sacrificial structure to thereby expose thebackside surface of the integrated circuit chip and at least a portionof the conductive portion conductively coupled to each of the pluralityof wire bonds.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIGS. 1A-1B depict an illustrative prior art packaged integrated circuitdevice;

FIGS. 2A-2C are various views of a packaged integrated circuit device inaccordance with various aspects of the present invention;

FIGS. 3A-3E are various views of one illustrative method of forming thedevice shown in FIGS. 2A-2C; and

FIG. 4 depicts an alternative embodiment of the conductive portion ofthe sacrificial structure.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that the description herein of specificembodiments is not intended to limit the invention to the particularforms disclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

The present invention will now be described with reference to theattached figures. Various regions and structures of a packagedintegrated circuit device are depicted in the drawings. For purposes ofclarity and explanation, the relative sizes of the various featuresdepicted in the drawings may be exaggerated or reduced as compared tothe size of those features or structures on real-world packaged devices.Nevertheless, the attached drawings are included to describe and explainillustrative examples of the present invention. The words and phrasesused herein should be understood and interpreted to have a meaningconsistent with the understanding of those words and phrases by thoseskilled in the relevant art. No special definition of a term or phrase,i.e., a definition that is different from the ordinary and customarymeaning as understood by those skilled in the art, is intended to beimplied by consistent usage of the term or phrase herein. To the extentthat a term or phrase is intended to have a special meaning, i.e., ameaning other than that understood by skilled artisans, such a specialdefinition will be explicitly set forth in the specification in adefinitional manner that directly and unequivocally provides the specialdefinition for the term or phrase.

FIGS. 2A-2C depict one illustrative embodiment of a packaged integratedcircuit (IC) device 100 in accordance with one aspect of the presentinvention. As shown in FIG. 2A, the device 100 comprises an integratedcircuit chip (IC chip) 102, a plurality of bond pads 104, a plurality ofwire bonds 106, each of which are conductively coupled to an exposedconductive portion 108. Also depicted in FIG. 2A is the exposed backside110 of the IC chip 102. An encapsulant material 105, e.g., an epoxy ormolding material, encapsulates the IC chip 102 except for the exposedbackside surface 110. FIG. 2B is a bottom view of the device 100. Asshown therein, the conductive portions 108 are positioned in theencapsulant material 105 around the perimeter of the IC chip 102. In theillustrative embodiment depicted in FIGS. 2A-2C, the exposed conductiveportions 108 are on substantially the same plane as the exposed backside110 of the IC chip 102. Moreover, in one illustrative embodiment, theexposed conductive portions 108 may have a generally circularcross-sectional configuration and a diameter 109 of approximately 16-80μm.

FIG. 2C is one illustrative example that depicts how the device 100 maybe conductively coupled to a conductive structure 28. The conductivestructure 28 may be any type of structure to which it is desired tooperatively couple an integrated circuit device, e.g., a printed circuitboard, a silicon interposer, a motherboard, flex tape, a memory module,etc. As shown therein, the device 100 may be operatively coupled to theconductive structure 28 by a plurality of solder balls 32 that areconductively coupled to the exposed conductive portions 108 and the bondpads 30 on the conductive structure 28. As will be recognized by thoseskilled in the art after a complete reading of the present application,the device 100 may be conductively coupled to the conductive structure28 by a variety of known techniques.

As will be recognized by those skilled in the art after a completereading of the present application, the packaged device 100 may beemployed with any type of IC chip 102, e.g., memory chips,microprocessors, ASICs, etc. Additionally, the precise shape, locationand material of the illustrative bond pads 104 and wire bonds 106 mayvary depending upon the particular application. Thus, the illustrativeembodiment depicted herein should not be considered a limitation of thepresent invention.

FIGS. 3A-3E depict one illustrative method of forming the packaged ICdevice 100. FIG. 3A depicts a plurality of singulated IC chips 102 thatare ready to be packaged. The IC chips 102 have been manufactured andsingulated using any of a variety of known processing techniques.Initially, as indicated in FIG. 3B, the IC chips 102 will be attached toa sacrificial structure 120 using, for example, an adhesive material 103or adhesive tape. The sacrificial structure 120 comprises at least someconductive material to which the wire bonds 106 will be attached, asdescribed more fully below. In the illustrative embodiment depicted inFIG. 3A, the sacrificial structure 120 comprises a substrate 122 and alayer of conductive material 124, e.g., a metal such as aluminum. In oneembodiment, the substrate 122 is comprised of a ceramic material and itmay have a thickness of approximately 0.135-0.5 mm. The substrate 122may also be comprised of other materials, such as an organic laminate,polymer, polyester, silicon, etc. The layer of conductive material 124may be deposited by a variety of known processes, e.g., sputterdeposition, and it may have a thickness of approximately 0.1-30 μm. Inthe illustrative embodiment depicted in FIG. 3A, the conductive portionof the sacrificial structure 120 takes the illustrative form of theconductive layer 124. However, other forms are also possible. Forexample, as shown in FIG. 4, the conductive portion of the sacrificialstructure 120 may take the form of a plurality of spaced-apartconductive structures 124A that correspond in location to the conductiveend portions 108 of the device 100. The spaced-apart conductive region124A may be of any desired shape, i.e., rectangular, rounded, etc. Otherstructures are also possible.

Next, as indicated in FIG. 3B, the wire bonds 106 are attached to the ICchips 102 and the conductive portion of the sacrificial structure 120,e.g., the illustrative conductive layer 124. The wire bonds 106 may becomprised of a variety of materials, e.g., gold, aluminum, copper, etc.,and they may be attached to the IC chip 102 and the conductive layer 124using a variety of known techniques. Attaching the wire bonds 106 to theconductive portion of the sacrificial structure 120 results in theformation of the conductive end portions 108. Thus, depending on theparticular materials of construction of the wire bond 106 and theconductive portion of the sacrificial structure 120, e.g., theconductive layer 124, the conductive end portions 108 may comprise acombination of such materials.

Then, as shown in FIG. 3C, an encapsulant 105, e.g., an epoxy materialor molding compound, is formed around the IC chips 102. The encapsulant105 may be comprised of a variety of known materials, such as epoxy,liquid encapsulant, epoxy mold compound, a powder, etc., and it may beapplied or formed around the IC chips 102 using a variety of knowntechniques.

As shown in FIG. 3D, one or more process operations are then performedto remove the sacrificial structure 120 thereby exposing the backside110 of the IC chips 102 and the exposed conductive portions 108. Thesacrificial structure 120 may be removed by a variety of techniques. Inone illustrative embodiment, the sacrificial structure 120 may beremoved by performing a planarization process. For example, thesacrificial structure 120 may be removed by performing one or morechemical mechanical polishing processes, by performing a grindingprocess, or by performing an etching process, or a combination of suchprocesses. The end result of these operations is a substantially planarsurface 105A which exposes the backside 110 of the IC chips 102 and theexposed conductive portions 108. FIG. 3E depicts three individualpackaged devices 100 after they have been singulated and after theencapsulant material 105 has been trimmed.

Through use of the present invention, the physical space occupied by thepackaged device IC 100 may be reduced as compared to prior art packagedIC devices. Since the present invention does not involve the formationof the relatively large conductive bond pads 22 on a carrier 14, asshown in FIG. 1A, the length and width of the overall packaged IC device100 may be reduced. For example, as shown in FIG. 2A, the horizontaldimension 111 from the edge of the IC chip 102 to the edge of theencapsulant material 105 may be approximately 0.1-0.4 mm. In contrast,the corresponding dimension 11 for the device 10 shown in FIG. 1A may beapproximately 0.5-1.0 mm. Thus, through use of the present invention,the “footprint” of the packaged IC device 100 may be reduced.Additionally, since the illustrative packaged IC device 100 disclosedherein does not comprise a carrier structure, like the carrier 14depicted in FIG. 1A, it occupies less vertical space, i.e., it isshorter, as compared to prior art packaged IC devices. For example, inone illustrative embodiment, the overall height 113 (see FIG. 2A) of thepackaged IC device 100 may range from approximately 0.1-0.5 mm.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. For example, the process steps set forth above may beperformed in a different order. Furthermore, no limitations are intendedto the details of construction or design herein shown, other than asdescribed in the claims below. It is therefore evident that theparticular embodiments disclosed above may be altered or modified andall such variations are considered within the scope and spirit of theinvention. Accordingly, the protection sought herein is as set forth inthe claims below.

1. A device, comprising: an integrated circuit chip comprising anexposed backside surface defining a plane; a plurality of wire bondsthat are conductively coupled to said integrated circuit chip, each ofsaid plurality of wire bonds being conductively coupled to a conductiveexposed portion having a lowermost surface, the entirety of thelowermost surface being positioned in said plane defined by saidbackside surface, said lowermost surface of said exposed portion havinga generally circular cross-sectional configuration within said plane;and an encapsulant material positioned adjacent said integrated circuitchip and said plurality of wire bonds, wherein a distance from a side ofsaid integrated circuit chip to a side of said encapsulant materialranges from approximately 0.1-0.4 mm and wherein a distance from saidbackside surface to a top surface of said encapsulant material rangesfrom approximately 0.1-0.5 mm.
 2. The device of claim 1, wherein saidintegrated circuit chip comprises at least one of a memory device, amicroprocessor and an application specific integrated circuit device. 3.The device of claim 1, wherein said wire bonds are comprised of gold. 4.The device of claim 1, wherein said wire bonds are comprised ofaluminum.
 5. The device of claim 1, wherein said wire bonds arecomprised of copper.
 6. The device of claim 1, wherein said exposedconductive portions are comprised of aluminum.
 7. (canceled) 8.(canceled)
 9. (canceled)
 10. The device of claim 1, wherein saidencapsulant material comprises an epoxy compound, a molding compound ora liquid encapsulant.
 11. The device of claim 1, wherein saidencapsulant material has a bottom surface that is substantiallypositioned in said plane.
 12. The device of claim 1, wherein saidbackside surface is a surface that has been subjected to at least oneprocessing operation after said encapsulant material is formed.
 13. Thedevice of claim 1, further comprising a conductive structure that isconductively coupled to said exposed conductive portions.
 14. The deviceof claim 13, wherein said conductive structure comprises a printedcircuit board, a silicon interposer, a motherboard, flex tape, or amemory module.
 15. The device of claim 13, wherein said integratedcircuit chip is conductively coupled to said conductive structure by aplurality of conductive balls.
 16. A device, comprising: an integratedcircuit chip comprising an exposed backside surface defining a plane; aplurality of wire bonds that are conductively coupled to said integratedcircuit chip, each of said plurality of wire bonds being conductivelycoupled to a conductive exposed portion having a lowermost surface, theentirety of the lowermost surface being positioned in said plane definedby said backside surface, said lowermost surface of said exposed portionhaving a generally circular cross-sectional configuration within saidplane; and an encapsulant material positioned adjacent said integratedcircuit chip and said plurality of wire bonds, said encapsulant materialcomprising a bottom surface that is positioned substantially in saidplane, wherein a distance from a side of said integrated circuit chip toa side of said encapsulant material ranges from approximately 0.1-0.4 mmand wherein a distance from said backside surface to a top surface ofsaid encapsulant material ranges from approximately 0.1-0.5 mm; and aconductive structure that is conductively coupled to said exposedconductive portions.
 17. The device of claim 16, wherein said integratedcircuit chip comprises at least one of a memory device, a microprocessorand an application specific integrated circuit device.
 18. The device ofclaim 16, wherein said wire bonds are comprised of at least one of gold,aluminum and copper.
 19. The device of claim 16, wherein said exposedconductive portions are comprised of aluminum.
 20. (canceled) 21.(canceled)
 22. (canceled)
 23. The device of claim 16, wherein saidconductive structure comprises a printed circuit board, a siliconinterposer, a motherboard, flex tape, or a memory module.
 24. The deviceof claim 16, wherein said integrated circuit chip is conductivelycoupled to said conductive structure by a plurality of solder balls.25-60. (canceled)